Rubbing machine with thrust-transmitting members

ABSTRACT

A rubbing machine of the type in which a support is spaced from and overlies a rubbing shoe and in which the rubbing shoe is connected to the support by a drive mechanism operable to gyrate the shoe. The rubbing shoe is rectangular in shape with the drive mechanism connected at the center of the shoe, and two flexible boots are connected between the support and the shoe on diametrically opposite sides of the drive mechanism. In the preferred embodiment, two pair of opposed, rigid studs are mounted between the support and the shoe to transmit thrust therebetween, and each pair of studs is mounted within a respective one of the boots with one of the studs connected to the support and one to the shoe. The opposed ends of the studs are smooth and positioned face-to-face so that the studs may slide on one another and still transmit thrust as the shoe gyrates.

United States Patent [72] lnventor Roy J Champayne c/o National-Detroit, Inc., 2810 Aulwin St., Rockford, Ill. 61 103 a [21 Appl. No. 828,857

[22] Filed May 29, 1969 [45] Patented May 4, 1971 [54] RUBB ING MACHINE WITH THRUST- 3,336,702 8/1967 Enders 5 III 70.5

ABSTRACT: A rubbing machine of the type in which a support is spaced from and overlies a rubbing shoe and in which the rubbing shoe is connected to the support by a drive mechanism operable to gyrate the shoe. The rubbing shoe is rectangular in shape with'the drive mechanism connected at the center of the shoe-, and two flexibleboots are connected between the support and the shoe on diametrically opposite sides of the drive mechanism. In the preferred embodiment, two pair of opposed, rigid studs are mounted between the support and the shoe to transmit thrust therebetween, and each pair of studs is mounted within a respective one of the boots with one of the studs connected to the support and one to the shoe. The opposed ends of the studs are smooth and positioned face-toface so that the studs may slide on one another and still transmit thrust as the shoe gyrates.

PATENTEUHAY 4:971 I 3577.687

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BACKGROUND OF THE INVENTION I This invention relates toa portable rubbing machine of the type used for sanding or polishing and, more particularly, to a machine in which a support is spaced from and overlies a rectangular rubbing shoe.- A drive mechanism is connected between the support and the shoe to drive the latter with a gyratory motion, and a number of flexible boots are connected between the support and the shoe to keep the shoe gyrating rather than rotating about the drive mechanism. In some prior artdevices, the boots are made of relatively stiff rubber to transmit thrust between the support and the shoe. Because the boots must be comparatively stiff in a vertical direction to' transmit thrust, they also are stiff in a lateral direction andv tend to resist the gyratory motion of the shoe. Thus, a great dea". of power is required to overcome the stiffness of the boots to gyrate the shoe thereby impairing the efficiency of the drive mechanism. Moreover, the lack of complete vertical rigidity of the stiff rubber boots results in the transmission of 1 some thrust to the drive mechanism and can cause the application of an excessive amount of stress on the drive mechanism.

SUMMARY OF THE INVENTION The primary object of the present invention is to provide a rubbing machine of the above type in which the thrust is transmitted between the support and the shoe by novel vertically stiff thrust transmitting members positioned within the boots to relieve the boots of the burden of transmitting thrust and thereby enable the use of boots which are extremely flexible in the lateral direction so as to greatly reduce the power required to gyrate the shoe.

It is a more detailed object to accomplish the above by each thrust transmitting member comprising a pair of opposed studs with one stud connected to the support and the other stud connected to the shoe and further with means interconnecting the studs to transmit thrust through the studs and between the support and the shoe. In one embodiment, the

studs are disposed in end-to-end relation with the means being the opposed ends of the studs, the ends being flat and smooth to reduce friction as the ends slide on one another during gyration of the shoe. In other embodiments, the means is a ball, or an elongated member disposed between the studs, and these means transmit thrust between the studs while allowing the studs to move laterally with respect to one another during gyration of the shoe.

Still another object is to keep as much of the weight of the studs as possibleon the support rather than the shoe. A further object is to help connect the boots to the support and the shoe by providing each stud with an enlarged radially extending flange which, when the studs are connected to the respective shoe or support, clamps a portion of the boot against the respective shoe or support.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of one embodiment of a new and improved rubbing machine embodying the novel features of the present invention.

FIG. 2 is an enlarged cross section taken substantially along the line 2-2 of FIG. I and showing one pair of the thrust-transmitting members positioned within a boot.

FIG. 3 is an enlarged cross section taken substantially along the line 3-3 of FIG. I and showing the shoe moved laterally of the support during gyratory movement.

FIG. 4 is an enlarged perspective view of the thrust-transmitting members shown in FIG. 2.

FIG. '1 is a perspective view of one part of the thrust-transmitting members of FIG. 6.

FIG. 8 is a cross-sectional view similar to FIG. 2 but showing another modification of the thrust-transmitting members.

FIG. 9 is a cross-sectional view similar to FIG. 2 but showing still another modification of the thrust-transmitting members.

' DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the drawings for purpose of illustration, the invention is embodied in a portable rubbing machine 10 (FIG. 1) driven by a rotary motor (not shown) mounted on a frame or support 11 on which a rubbing shoe 12 is supported for bodily gyration. The support is a horizontal, elongated diamond-shaped member with downtumed edges 13 (FIG. 3) and is spaced from and overlies the rubbing shoe. To support and house the rotary motor, a housing 14 (FIG. 1) is mounted on the support.

To drive the rotary motor, air under pressure is carried to the motor through the housing 14 by a flexible tube 15. To enable the user to grip the rubbing machine and to control the air supply to the motor, a handle 16 is attached to the housing and extends around the tube. Overlying the handle is a lever 17 which is operatively connected to a valve (not shown) so that, by pressing down on the lever, the valve may be opened to operate the motor.

The rubbing shoe I2 comprises a pad 18 (FIG. 3) of yieldable material such as rubber adhesively secured to a metal sheet 19 whose edges 20 are upturned. An abrasive sheet 21 is stretched around the bottom of the pad andis fastened to the latter at opposite ends by suitable clamps 22 (FIG. I)

'about the upper end and, since the shoe is connected to the crank,-the shoe moves with the lower offset end and gyrates relative to the support 11.

Rubber boots 25 (FIG. I) are connected between the support 11 and the rubbing shoe 12 to hold the shoe against turning during its gyratory motion. Herein, two boots are used and are located on diametrically opposite sides of the crank '23. As shown in FIG. 2, the boots are round hollow pieces of rubber adhesively secured to and seated in ferrules 26 (FIGS. 2 and 3) which are fastened to the underside 27 of the support 11 and the top side 28 of the metal sheet 19; As the shoe gyrates,

- tion but to prevent rotation of the shoe about the crank.

' forward end of the support 11 with his other hand. The user FIG. 5 is an enlarged fragmentary cross section taken substantially along the line 5-5 of FIG. 1.

FIG. 6 is a cross-sectional view similar to FIG. 2 but showing a modification of the thrust-transmitting members.

then exerts a downward pressure or thrust against the support. This thrust is transmitted to the shoe to pressit firmly against the work surface. The knob 29 also is used .to guide. the rubbing machine 10 during operation. Because of the length of the shoe, the thrust should be transmitted to several spaced points rather than at one central point to insure uniform pressure of all portions of the shoe against the surface.

In accordance with the present invention, the thrust is transmitted between the support 11 and the rubbing shoe 12 at the same points as the connections of the boots 25 to the shoe and the support and in a manner which not only requires no thrusttransmitting capability from the boots but which also allows great lateral flexibility of the boots so as to reduce the power required to gyrate the shoe. In the preferred embodiment these ends are accomplished by a pair of rigid upright studs 30 and 31 (FIG. 3) which are housed within each boot in end-toend engagement with the upper stud 30 connected to the support and with the. lower stud 31 connected to the shoe, the engaging ends 32 and 33 of the studs being smooth to reduce friction so as to allow sliding of one on the other. With this arrangem'ent, thrust is transmitted between the support and the shoe at the proper points and in a positive manner, the life of the boots is greatly increased since the boots themselves do not transmit thrust and, at the same time, the thickness of the walls of the boots can be kept to a minimum to allow a great deal of lateral flexiblity and thus allow the shoe to be gyrated with less power. Moreover, the studs are protected from dirt by virtue of their encasement within the boots, and the crank 23 is relieved of any thrust stresses that otherwise would be applied as a result of the downward pressure exerted on the machine.

ln this instance, preferably are made of a rigid material such as that sold under the trade-name Synthane with a low coefficient of friction although any rigid material may be used. So that the upper stt'd 30 of each pair may be fastened rigidly to the support 11 and the lower stud 31 may be fastened to the shoe 12, the ends 34 of each boot 25 (FIG. 2) are formed with holes 36 extending into the hollow interior of the boot. As shown in FIG. 2, the studs are positioned between the support and the shoe within the boot and are disposed in end-to-end engagement with one another. The studs are slightly smaller in diameter than the holes 36 and both are smaller in diameter than the hollow interior of the boot. The studs fit through the holes and lie flat against the ferrules 26, and the studs are fastened to the support and the shoe by screws 37 and 370 (FIG. 2).

Because the shoe l2 gyrates with respect to the support 11 and the lower stud 31 moves laterally with the shoe, the engaged ends or faces 32 and 33 of the studs 30 and 31 must be able to slide on one another. Each of the faces herein is a flat surface which is finished smooth and which is positioned parallel with the rubbing surface of the shoe. Also because the shoe gyrates, the hollow interior of each boot 25 must be larger than the enclosed studs so that, as shown in FIG. 3, the interior of the boot can accommodate the position of both studs when the lower stud 31 moves laterally with the shoe 12 with respect to the support 11 and the upper stud 30.

To help hold the boot 25 in the ferrules 26 and to help hold the hollow interior of the boot at its normal diameter, each stud 30 and 31 is formed with an enlarged radially extending flange 38 (HO. 4). This flange is the same diameter as the hollow interior of the boot and is spaced axially from the connected end of each stud a distance equal to the thickness of the end 34 of the boot. With this arrangement, each stud, when it is connected to either the shoe or the support, clamps its respective end of the boot against the end of the associated ferrule.

So that the faces 32 and 33 of each pair of studs 30 and 31 are lubricated, the interior of each boot 25 is filled with lubricant. To place the lubricant in the boot, the upper stud is formed with an axial bore 39 (FIG. 3) through its entire length, and the top portion of the bore is threaded. The upper stud is connected to the support 11 by the screw 37a which is passed through a hole 380 (FIG. 2) in the support and screwed into the threaded portion sembly, the lubricant is, injected through the holes 38a and 39 into the interior of the boot. The screw 37a is then threaded into the bore 30 to connect the upper stud to the support and seal off the interior of the boot so that no foreign matter can come between the faces of the studs to cause wear of the faces.

So that the shoe 12 will gyrate which each point on the shoe makes a perfect circle, the moving parts of the rubbing machine are dynamically balanced. To reduce the amount of additional and unbalanced weight placed the shoe by the studs, the lower stud 31 is much shorter in length (FIG. 2) than the upper stud 32. With the lower stud being as short as possible, the amount of weight added to the shoe is kept to a minimum with an attendant low frequency of undesirable vibrations caused by improper weight distribution.

in a perfect path, one in the studs 30 and 31 are cylinders whichof the hole 39. During final as-- 'the depressions.

With the studs 30 and 31 transmitting the thrust between the support 11 and the rubbing shoe 12, the crank 23is connected to the shoe only to gyrate the shoe bodily and is relieved of any thrust stresses that otherwise would be applied as a result of the downward pressure exerted on the machine. As shown in FIG. 5, the lower offset end portion 24 of the crank is slidably fitted into a bearing 40 which is held on the shoe by a bearing cup 41 rigid with the shoe. The lower offset end portion of the crank is free to move vertically in the bearing to insure that the crank is not stressed by any thrust transmitted I between the support and the shoe.

A modification of the thrust-transmitting members is shown in FIG. 6. In this modification, the thrust-transmitting members are in three parts rather than two. Connected to the support 11 is an upper stud or button 50 and connected to the shoe 12 is a lower stud or button 51. These buttons are two of the three parts of the thrust-transmitting members. Each button is formed with cylindrical neck portion 52 which is inserted in the hole 36 in the respective end of the boot 34 with one end, the connected end, fitted flush against the respective ferrule 26. The other end of each button is formed with an enlarged radially extending flange 53. This flange is the same diameter as the hollow interior of the boot 25 and isspaced axially from the connected end a distance equal to the thickness of the end 34 of the boot. Between the lower face 54 of the upper button and the upper face 55 of the lower button, a vertically positioned cylindrical'member 56 is positioned with its upper face flat against the lower face of the upper button and with its lower face flat against the upper face of the lower button. This cylindrical member forms the third part of the three-part thrust-transmitting members. With this arrange ment, the lower face 54 of the upper button may slide on the upper face of the cylindrical member during gyratory movement of the shoe 12 and the upper face 55 of the lower button may also slide on the lower face of the cylindrical member during such movement.

Another modification is shown in FIG. 8 and is somewhat similar to that of H0. 6. The lower face 54a of the upper button 50 and the upper face 550 of the lower button are each formed with a curved depression 60. Fitted between these two buttons and seated in the depressions is an elongated vertically stiff member 61 with ends 62 which are rounded to mate with With this arrangement, the buttons do not slide on the member 61 but rather the member rotates in an inclined circular path about its upper end as the shoe gyrates.

In FIG. 9, still another modification is depicted. Here, the member which transmits thrust between the buttons 50 and 51 is a ball 70. Formed on the upper face 54 and lower face 55 respectively of the lower and upper buttons are short studs 71 each containing a depression 72 to receive the ball. As shown, each depression is circular with a flat surface 73 in contact with the ball and with curved sides 74. As the shoe 12 gyrates, the ball is rolled about the flat surfaces of the depressions to allow lateral flexing of the boot 25.

It will be observed that the placement of thrust-transmitting members which each boot 25 to transmit thrust between the support and the shoe is a particularly beneficial arrangement. With this arrangement, the thrust is positively transmitted between the support 11 and the shoe 12 while the boots are free to flex laterally without being required to transmit thrust. As a result, thin-walled and extremely flexible boots may be used to reduce the power necessary to gyrate the shoe. Since the boots are used only to resist-turning of the shoe during its gyratory movement, only two boots are required, and these need replacement much less often than would be required placement much le if the boots also transmitted the thrust. With the studs positioned within the boots, the studs are kept clean so that the faces do not wear out quickly.

hollow and laterally flexible boot connected between the support and the shoe and spaced angularly from one another around the drive mechanism, andvertically stiff transmitting transmitting means comprises two vertically stiff and, generally means housed within said boots'and connected between the support and the for transmitting thrust between the support and the shoe while permitting lateral flexing of the boots.

2, The rubbing machine of claim 1 in which each. thrusttransmitting means comprises two vertically stiff and generally upright studs positioned in end-to-end engagement, the upper stud being connected to the support and the lower stud being connected to the shoe, and said studs being movable laterally with respect to one another while remaining in end-to-end engagement as the shoe gyrates.

3. The rubbing machine of claim 2 in which the studs in each. boot are of unequal length and in which the longer stud is.

connectedv to the support so that the majority of the weight of the studs is carried by the support. a

4. The rubbing machine of claim 2 in which the ends of each 'ooot are of a predetemiined thickness and have a hole of a size slightly larger in diameter than the studs, the respective studs extending through the respective holes and being connected to the respective support or shoe, each of said studs being formed with an enlarged radially extending flange spaced from the connected end of the stud a distance equal to said predetermined thickness whereby the respective ends of each boot are clamped against the respective flange.

5.- The rubbing machine of claim 1 in which each thrustrespective support or shoe by the transmitting means comprises two vertically stiff and generally each with a curved depression, and an elongated vertically stiff memberhaving curved ends disposed between the faces of said buttons with the curved ends seated in said depressions. r

I; Therubbing machineof claim 1 iniwhich said thrustuprig'ht'buttons' with one connected to said support and the other to said shoe, said buttons having opposed faces each formed with a depression and a ball disposed between said buttons and seated in said depressions.

8. A rubbing machine having, in combination, a generally rectangular rubbing shoe, a rigid elongated support spaced from and overlying the shoe, a drive mechanism connected between the support and the shoe and operably connected to the shoe intermediate the ends of the shoe to gyrate the latter relative to the support, two hollow and laterally flexible boots connected between the support and the shoe and positioned on diametrically opposite sides of the drive mechanism,

thrust-transmitting means housed within each boot, each of said thrust-transmitting means comprising a lower rigid stud connected to the shoe and extending upwardly toward the support, an upper rigid stud connected to the support and ex tending downwardly toward the shoe, and means interconnecting'the studs to transmit thrust between the studs and between the support and the shoe while permitting relative lateral movement of the studs to enable lateral flexing of the boots and gyration of the shoe.

9. The rubbing machine of claim 8 in which the ends of each boot are of a predetermined thickness and have a hole of a size slightly larger in diameter than the studs, the respective studs extending through the respective holes and being connected to the respective support or shoe, each of said studs being formed with an enlarged radially extending flange spaced from the connected end of the stud a distance equal to said predetermined thickness whereby the respective ends of each boot are clamped against the respective support or shoe by the respective flange.

10. The rubbing machine of claim 8 in which means com-- prise an upper surface of said lower 'stud and a lower surface of said upper stud, said surfaces being disposed in sliding faceto-face engagement.

ll. The rubbing machine of claim 8 in which said means is a :balldisposed between said upper stud and said lower stud.

' 12. The rubbing machine of claim 8 in which said'means is a vertically elongated member disposed between said upper stud and said lower stud. 

1. A rubbing machine having, in combination, a rubbing shoe, a rigid support spaced from and overlying the shoe, a drive mechanism connected between the support and the shoe and operable to gyrate the shoe relative to the support, two hollow and laterally flexible boot connected between the support and the shoe and spaced angularly from one another around the drive mechanism, and vertically stiff transmitting means housed within said boots and connected between the support and the for transmitting thrust between the support and the shoe while permitting lateral flexing of the boots.
 2. The rubbing machine of claim 1 in which each thrust-transmitting means comprises two vertically stiff and generally upright studs positioned in end-to-end engagement, the upper stud being connected to the support and the lower stud being connected to the shoe, and said studs being movable laterally with respect to one another while remaining in end-to-end engagement as the shoe gyrates.
 3. The rubbing machine of claim 2 in which the studs in each boot are of unequal length and in which the longer stud is connected to the support so that the majority of the weight of the studs is carried by the support.
 4. The rubbing machine of claim 2 in which the ends of each boot are of a predetermined thickness and have a hole of a size slightly larger in diameter than the studs, the respective studs extending through the respective holes and being connected to the respective support or shoe, each of said studs being formed with an enlarged radially extending flange spaced from the connected end of the stud a distance equal to said predetermined thickness whereby the respective ends of each boot are clamped against the respective support or shoe by the respective flange.
 5. The rubbing machine of claim 1 in which each thrust-transmitting means comprises two vertically stiff and generally upright buttons with one connected to said support and one connected to said shoe, said buttons having flat opposed faces, and an upright member with flat top and bottom faces disposed between said buttons in face-to-face relationship therewith whereby the faces of the buttoNs may slide on the respective faces of the upright positioned member as said shoe gyrates.
 6. The rubbing machine of claim 1 in which each thrust-transmitting means comprises two vertically stiff and generally upright buttons with one connected to said support and one connected to said shoe, said buttons having opposed faces each with a curved depression, and an elongated vertically stiff member having curved ends disposed between the faces of said buttons with the curved ends seated in said depressions.
 7. The rubbing machine of claim 1 in which said thrust-transmitting means comprises two vertically stiff and generally upright buttons with one connected to said support and the other to said shoe, said buttons having opposed faces each formed with a depression and a ball disposed between said buttons and seated in said depressions.
 8. A rubbing machine having, in combination, a generally rectangular rubbing shoe, a rigid elongated support spaced from and overlying the shoe, a drive mechanism connected between the support and the shoe and operably connected to the shoe intermediate the ends of the shoe to gyrate the latter relative to the support, two hollow and laterally flexible boots connected between the support and the shoe and positioned on diametrically opposite sides of the drive mechanism, thrust-transmitting means housed within each boot, each of said thrust-transmitting means comprising a lower rigid stud connected to the shoe and extending upwardly toward the support, an upper rigid stud connected to the support and extending downwardly toward the shoe, and means interconnecting the studs to transmit thrust between the studs and between the support and the shoe while permitting relative lateral movement of the studs to enable lateral flexing of the boots and gyration of the shoe.
 9. The rubbing machine of claim 8 in which the ends of each boot are of a predetermined thickness and have a hole of a size slightly larger in diameter than the studs, the respective studs extending through the respective holes and being connected to the respective support or shoe, each of said studs being formed with an enlarged radially extending flange spaced from the connected end of the stud a distance equal to said predetermined thickness whereby the respective ends of each boot are clamped against the respective support or shoe by the respective flange.
 10. The rubbing machine of claim 8 in which means comprise an upper surface of said lower stud and a lower surface of said upper stud, said surfaces being disposed in sliding face-to-face engagement.
 11. The rubbing machine of claim 8 in which said means is a ball disposed between said upper stud and said lower stud.
 12. The rubbing machine of claim 8 in which said means is a vertically elongated member disposed between said upper stud and said lower stud. 